Shipping container for radioactive material

ABSTRACT

The body means of the shipping container includes an inner shell means and an outer shell means spaced outwardly of the inner shell means, radiation shielding material being disposed within the space between the inner and outer shell means. The inner shell means defines a radioactive material receiving cavity therewithin having a cross-sectional configuration defining three sides, adjacent ones of the sides joining one another to define three apexes to thereby provide maximum capacity with a minimum size and weight container.

Elle @KQKQS 1 [111 Bfififidit Peterson et at. 1 May 1, 1973 [54] SHIPPING CONTAINER FOR 3,588,509 6/1971 Yanagishita et al. ..250 10& R RADHQACTHVE MATERIAL 3,532,883 10/1970 Dresia et al. ..250/l08 R X [75] Inventors: Reuben W. Peterson, Wilmington, Primary Examiner Archie R Borchelt Del.; Harold A. Backus, Wynwood,

Assistant Examiner-Davis L. Willis Pa.; Clifford J. Anderson, B AttorneyRobert L. Lehman, Fred Floersheimer and uckeystown, Md.

Jay D. Gordon [73] Assignee: N L Industries, Inc., New York,

57 ABSTRACT [22] Filed: Apr. 14, 19 7 1 The body means of the shipping container includes an [21] Appl' NOJ 133,966 inner shell means and an outer shelhmeans spaced outwardly of the inner shell means, radiation shielding material being disposed within the space between the U-S- CL a R inner and outer she means The inner shell means [51] n a t ..G2lf defines a radioactive material receiving cavity [58] Field of Search ..250/ 106 R, 106 S, therewithin having a cross sectional fi i n 250/108 108 WS defining three sides, adjacent ones of the sides joining one another to define three apexes to thereby provide [56] References C'ted maximum capacity with a minimum size and weight UNITED STATES PATENTS wmamer- 3,179,243 4/1965 Ashcroft ..250/l08 R x 18 Claims, 8 Drawing Figures 3,526,080 9/1970 Senkewich ..250/l06 R X Patented May -1, 1973 3 Sheets-Sheet 1 MN m M 00 EUSS WKHR E BDIA Aw 0 m m m B MU I EL HRC 5 Sheets-Sheet 3 INVENTO RS HAROLD A. BACKUS REUBEN W. PETERSON 8| 7 SON CLIFFORD J. ANDER SHIPPING CONTAINER FOR RADIOACTIVE MATERIAL BACKGROUND OF THE INVENTION The present invention relates to a new and novel shipping container for radioactive material, and more particularly to a shipping container which is especially adapted to ship spent fuel elements utilized in nuclear reactors and the like.

The present invention may be employed for shipping various types of radioactive material and is particularly suited for shipping irradiated nuclear fuel elements, the container normally being mounted on railroad cars, trailers and the like for transport from one place to another.

Such shipping containers must of course provide adequate containment radiation protection for personnel in the area of the container, and in addition the container must provide adequate physical protection and decay heat dissipation for the radioactive material during shipment, and accordingly the shipping container must be of a strong and rugged construction.

Present-day nuclear fuel elements are of square cross-section, and conventional shipping containers are generally of square or circular cross-sectional configuration including a square or circular cavity therewithin for receiving the fuel elements. When employing relatively small shipping containers for transport overland by trailer or truck, shipping containers having cylindrical cavities therewithin are uneconomical since the fuel elements of square cross-sectional configuration cannot be fitted in an optimum manner into a cavity of circular cross-sectionalv configuration without considerable open wasted space and excessive shielding weight.

Casks of square cross-section are also undesirable due to the fact that the cost of manufacture thereof is quite great and, furthermore, the strength and struc- The ideal solution is to wrap the radiation shielding material around the fuel elements in such a manner as to minimize the shielding weight which comprises the largest portion of the weight of the shipping container. However, it is also desirable to provide a shipping container having walls of arcuate configurations for ease and economy of construction and to provide the higher integrity associated with curved wall constructions such as cylinders and the like. It is accordingly a principal objective of the present invention to provide a shipping container having a maximum capacity for fuel elements while having'a minimum amount of weight and allowing reasonably economical construction wherein the members of the shipping container can be generated by conventional tools.

When shipping containers for radioactive material are transported by truck or trailer, the overall weight is limited by the regulations of the highways being used.

' The economics of the situation require the greatest payload in the form of fuel elements for a given gross weightvof tractor, trailer, shipping container and its contents;

The shipping container may be either a single type container which is dimensionally designed to allow shipping of certain maximum number of fuel elements of a specific size, or a multiple type shipping container may be'provided which is designed to accommodate two or more different size fuel elements. Single type shipping containers used in repeated cycle transportation movement require the availability of a large number of fuel elements of the specified size in order to allow economical cost of operation. On the other hand,

multiple type shipping containers have a major advantage in that they are available for transportation of either of two or more types of fuel elements thereby permitting the schedules of shipping to be optimized as well as increasing the gross number of elements that may be transported.

It is accordingly a further important feature of the present invention to provide a multiple purpose shipping container which is adapted to ship the two present major types of fuel elements, namely, pressurized water reactor fuel elements which are approximately 8% inches square or boiling water reactor fuel elements which are approximately 5% inches square.

SUMMARY OF THE INVENTION In the present invention, a shipping container is provided including an inner shell means and an outer shell means spaced outwardly of the inner shell means, radioactive shielding material being disposed in a space between the inner and outer shell means. The inner shell means defines a radioactive material receiving cavity therewithin which has a cross-sectional configuration defining three sides, adjacent ones of the sides joining one another to define three apexes. The three sides are of substantially equal length and configuration to define a symmetrical cavity. Substantially equal angles are defined between adjacent sides of the cavity, these angles being 90 or greater.

In one form of the invention, the sides may be formed as con-tinuous curves which is of particular advantage since it enables convenient methods of manufacture in machining arcuate surfaces.

In a further form of the invention, the sides may inelude a pair of straight portions joined by intermediate curved portions, and in a still further modified form of the invention the sides may comprise a plurality of straight portions disposed at an angle to one another.

The construction of the present invention combines the desirable feature of wrapping the shielding material around the fuel elements as tightly as possible while providing a construction which is strong and rugged and which may be manufactured in'an economical manner.

The present invention provides minimum weight of the shipping container for a given payload content. This is particularly important in connection with shipping containers to be used on trucks which move over highways wherein weight is a critical factor.

Additionally, the construction of the present invention provides a multiple purpose shipping container which is designed to effectively receive fuel elements of different cross-sectional dimensions thereby substantially enchancing the versitility of the container.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top perspective view of a shipping container accord-ing to the present invention;

FIG. 2 is a sectional view partially broken away and on an enlarged scale taken substantially along line 2-2 of FIG. 1 looking in the direction of the arrows;

FIG. 3 is a sectional view on an enlarged scale taken substantially along line 3-3 of FIG. 2 looking in the direction of the arrows;

FIG. 4 is a sectional view illustrating a modified form of the invention;

FIG. 5 is a sectional view illustrating a further manner of utilizing the structure shown in FIG. 4;

FIG. 6 is a sectional view illustrating still another form of the invention;

FIG. 7 is a sectional view illustrating a further manner of utilizing the structure shown in FIG. 6; and

FIG. 8 is a sectional view illustrating a further modification of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS I cording to the present invention is illustrated in FIGS.

1-3 andcomprises a body means including an inner shell means 10 having a bottom l2.and an outer shell means 14 having a bottom 16, the outer shell means being spaced outwardly of the inner shell means. Each of these shell means may be formed of stainless steel or other suitable material.

Radiation shielding material is disposed in the space between the inner and outer shell means and may take the form of any suitable gamma radiation shielding substance. As illustrated, a uranium casting is provided in the annular space between the inner and outer shell means and defines the usual void 22 at the upper portion of the shipping container. This uranium casting may be in a plurality of sections depending on the size of the container. A further uranium casing 24 is disposed adjacent the bottom 12 of the inner shell means and has a suitable joint with uranium casting 20 to prevent radiation beaming between the two castings. A further body of lead shielding material 26 may be disposed between casting 24 and the bottom 16 of the outer shell means for improved impact protection if desired.

A top closure means 30 is hollow and includes an uranium casting 32 and a body of lead 34 to provide the desiredradiation shielding and impact protection in the closure means. Aplu'rality of threaded set screws 36 are threaded through suitable holes provided in the body means and bear upon a conical surface 37 machined into the closure means to enable the closure means to be positioned without regard to alignment with the set screws which serve to hold the closure meansin the operative position illustrated. A seal 38 of conventional construction is provided between the body means and the closure means.

A plurality of horizontally disposed annular fins 40 including portions of arcuate configuration are disposed in surrounding relationship to the outer shell means and are suitably spaced from one another, the fins having disposed therebetween suitable hydrogenous neutron shielding material 42.

As seen particularly in FIG. 3, inner shell means 10 defines a radioactive material receiving cavity therewithin, said cavity having a cross-sectional configuration defining three sides 50, 52 and 54. Adjacent ones of the sides join one another to define three apexes 56, 58 and 60. The three aides are all of substantially equal length and configuration, each of the sides being formed by a continuous are, it being apparent that the inner shell means comprises three similar arcuate members which are welded to one another along the longitudinal seams thereof. In this manner, a substantially symmetrical cavity is provided. The three sides define inner substantially equal angles therebetween, the angles between adjacent sides each being greater than 90 in this embodiment of the invention.

The configuration shown in FIG. 3 provides space for seven boiling water reactor fuel elements 64, these fuel elements being retained in the operative position illustrated by spacer means 66 formed of a suitable aluminum alloy or the like which serves as a heat conductor and which further serves to absorb neutrons to provide criticality control during shipment. The spacer means extends the full length of the fuel elements and is suitably fastened in place.

Also indicated in phantom lines in FIG. 3 are three pressurized water reactor fuel elements 70 which can be substituted in place of the seven boiling water reactor fuel elements illustrated in solid lines, it being understood that a different spacer means would be employed with the pressurized water reactor fuel elements 70. It is accordingly apparent that the shipping container of the present invention is of the multiple purpose type which is equally adapted to ship fuel elements of different sizes.

Referring now to FIG. 4, a modification of the invention is illustrated wherein the inner shell means is of modified construction so as to provide a radioactive material receiving cavity having a slightly different cross-sectional configuration. It should be understood that the remaining components of the shipping container will be substantially identical to those previously described, and the outer shell means may either be complementary to the configuration of the inner shell means or it may be of identical construction to the outer shell means 14 previously described.

In "the form of the invention shown in FIG. 4, the cavity has a cross-sectional configuration including three sides 82, 84 and 86. These sides are of substantially equal length and configuration 'to define a symmetrical cavity. Each side includes a pair of straight portions at the opposite ends of this side interconnected by a central curved portion. The straight portions at'the ends of the sides join with one another to provide substantially right angles at the apex portions 90, 92 and 94.

A fuel element 100 is disposed within the cavity and is retained in place by an aluminum insert 102 and a suitable aluminum alloy spacer 104.

Referring now to FIG. 5, the inner shell means is illustrated as being utilized in association with a fuel element 1 10 which is somewhat larger than the fuel element shown in FIG. 4. A suitable spacer 112 is employed for holding the fuel element in operative position. Three fuel elements 116 are illustrated in phantom lines, it being understood that these fuel elements of smaller dimension can be positioned in the cavity in place of the single fuel element illustrated in solid lines, it being understood that a suitable spacer means of different configuration would be employed with fuel elements 116.

Referring now to FIG. 6 of the drawing, a further modification of the invention is illustrated wherein an inner shell means 120 of modified construction is provided to define a radioactive material receiving cavity of slightly different cross-sectional configuration. The remaining components of the shipping container may be substantially the same as those previously described, the outer shell means being either complementary to the inner shell means 120 or of a construction identical to outer shell means 14 previously described.

In the form of the invention shown in FIG. 6, the cavity defines three sides 122, 124 and 126 all of which are of substantially equal length and of substantially the same configuration. Each of these sides comprises two straight portions of each of the sides being disposed at an angle to one another. The cavity is again of symmetrical configuration.

Adjacent ones of the sides define substantially equal angles therebetween, the angles at the apexes 128, 130 and 132 each being substantially 90 in this form of the invention.

Three fuel elements 136 are illustrated in operative position within the cavity, these fuel elements being retained in operative position by aluminum inserts 138 and suitable spacer means 140.

Referring now to FIG. 7, inner shell means 120 is illustrated as being associated with six fuel elements 144 retained in operative position by a suitable spacer means 146, acentral void 148 being provided within the spacer means. Here again, it is apparent that the form of the invention as shown in FIGS. 6 and 7 is of the multiple purpose type which enables fuel elements of different size to be operatively associated therewith.

Referring now to FIG. 8, still another modified form of the invention is illustrated including an inner shell means 150 which may be of substantially the same con struction as all inner shell means 120 previously described, Inner shell means 150 includes three similar sides 152, I54 and 156, the sides intersecting one another to define three equally spaced apexes 158.

In this form of the invention, the outer shell means 160 is of circular cross-sectional configuration so as to provide maximum strength to the shipping container at minimum cost. A first radiation shielding material 162 which may comprise lead is disposed between the inner and outer shell means. It will be noted that the apexes of the inner shell means are disposed closer to the outer shell meansthan the remaining portions of the inner shell means. In order to provide adequate shielding outwardly of the apexes, suitable corner shield means 164 are provided adjacent each of the apexes. These corner sheld means comprise uranium castings which have a maximum thickness in a radial direction directly outwardly of the associated apex of the inner shell means, the uranium castings tapering to a smaller thickness toward the central portions of the walls of the inner shell means. In this manner, it is possible to establish uniform shielding conditions throughout the entire structure.

The side surfaces 166 of each of the corner shielding means are arcuate to provide a curved or otherwise non-planar interface between the corner shielding means and the body of lead to avoid beaming of radiation from the radioactive material within the cavity along the interface of the lead and uranium castings in case the lead is not bonded to the uranium.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

What is claimed is:

1..A shipping container for radioactive material comprising body means including an inner shell means and an outer shell means spaced outwardly of said inner shell means, radiation shielding material disposed in the space between said inner and outer shell means, said inner shell means defining a cavity for reception of (a) radioactive material elements (receiving cavity therewithin), said cavity having a cross-sectional configuration defined by three curvilinear sides, (defining three sides) adjacent ones of which are integrally joined together (said sides joining one another) to define three apexes, and spacer means in said cavity arranged in combination with the curvilinear sides and apexes thereof to provide maximum number of radioactive material elements in said cavity with minimum number of spacer means.

2. A shipping container as defined in claim 1 wherein said sides of the cavity are all of substantially equal length.

3. A shipping container as defined in claim 1 wherein said sides of the cavity are all of substantially the same configuration.

4. A shipping container as defined in claim 1 wherein said sides of the cavity are all of substantially equal length and of substantially the same configuration to define a cavity which is of symmetrical cross-sectional configuration.

5. A shipping container as defined in claim 1 wherein adjacent ones of said sides define substantially equal angles therebetween.

6. A shipping container as defined in claim 5 wherein said angles are at least or more.

7. A shipping container as defined in claim 1 wherein each of said sides comprises a continuous curve.

8. A shipping container as defined in claim 1 wherein each of said sides includes a plurality of straight portions interconnected with one another by a curved portion.

9. A shipping container as defined in claim 8 wherein each of said sides includes a pair of straight portions at the opposite ends thereof interconnected by a central curved portion.

10. A shipping container as defined in claim 1 wherein each of said sides includes a plurality of straight portions disposed at an angle to one another.

1 1. A shipping container as defined in claim 1 including comer shielding means disposed adjacent said apexes, said corner shielding means being formed of a further radiation shielding material more dense than said first mentioned shielding material.

12. A shipping container as defined in claim 11 wherein said first mentioned shielding material comprises lead, said comer shielding means comprising a material of higher density than lead.

13. A shipping container as defined in claim 11 wherein the outer surface of said corner shielding means is curved to define a non-planar interface between said corner shielding means and said first mentioned shielding material to prevent beaming of radiation along the interface of the first mentioned shielding material and said corner shielding means.

14. A shipping container as defined in claim 1 including a closure means for one end of the container, said closure means having a conical surface formed thereon, and members connected with the body means and engageable with said surface for holding the closure means in operative position.

15. A shipping container as defined in claim 1 wherein said outer shell means includes sides of arcuate 

1. A shipping container for radioactive material comprising body means including an inner shell means and an outer shell means spaced outwardly of said inner shell means, radiation shielding material disposed in the space between said inner and outer shell means, said inner shell means defining a cavity for reception of (a) radioactive material elements (receiving cavity therewithin), said cavity having a cross-sectional configuration defined by three curvilinear sides, (defining three sides) adjacent ones of which are integrally joined together (said sides joining one another) to define three apexes, and spacer means in said cavity arranged in combination with the curvilinear sides and apexes thereof to provide maximum number of radioactive material elements in said cavity with minimum number of spacer means.
 2. A shipping container as defined in claim 1 wherein said sides of the cavity are all of substantially equal length.
 3. A shipping container as defined in claim 1 wherein said sides of the cavity are all of substantially the same configuration.
 4. A shipping container as defined in claim 1 wherein said sides of the cavity are all of substantially equal length and of substantially the same configuration to define a cavity which is of symmetrical cross-sectional configuration.
 5. A shipping container as defined in claim 1 wherein adjacent ones of said sides define substantially equal angles therebetween.
 6. A shipping container as defined in claim 5 wherein said angles are at least 90* or more.
 7. A shipping container as defined in claim 1 wherein each of said sides comprises a continuous curve.
 8. A shipping container as defined in claim 1 wherein each of said sides includes a plurality of straight portions interconnected wiTh one another by a curved portion.
 9. A shipping container as defined in claim 8 wherein each of said sides includes a pair of straight portions at the opposite ends thereof interconnected by a central curved portion.
 10. A shipping container as defined in claim 1 wherein each of said sides includes a plurality of straight portions disposed at an angle to one another.
 11. A shipping container as defined in claim 1 including corner shielding means disposed adjacent said apexes, said corner shielding means being formed of a further radiation shielding material more dense than said first mentioned shielding material.
 12. A shipping container as defined in claim 11 wherein said first mentioned shielding material comprises lead, said corner shielding means comprising a material of higher density than lead.
 13. A shipping container as defined in claim 11 wherein the outer surface of said corner shielding means is curved to define a non-planar interface between said corner shielding means and said first mentioned shielding material to prevent beaming of radiation along the interface of the first mentioned shielding material and said corner shielding means.
 14. A shipping container as defined in claim 1 including a closure means for one end of the container, said closure means having a conical surface formed thereon, and members connected with the body means and engageable with said surface for holding the closure means in operative position.
 15. A shipping container as defined in claim 1 wherein said outer shell means includes sides of arcuate cross-sectional configuration.
 16. A shipping container as defined in claim 15 wherein said cavity has a cross-sectional configuration different from said outer shell means, and a separate closure means for said container of substantially circular cross-sectional configuration.
 17. A shipping container as defined in claim 1 wherein said radiation shielding material is of arcuate cross-sectional configuration.
 18. A shipping container as defined in claim 1 including fins having portions of arcuate configuration disposed outwardly of said outer shell means. 